U.S. patent number 9,357,111 [Application Number 14/129,465] was granted by the patent office on 2016-05-31 for casing.
This patent grant is currently assigned to QINETIQ LIMITED. The grantee listed for this patent is Jim Maurice Abbey, Christopher Mark Driscoll, David Simpson, Daniel John White, Clive Charles Woolley. Invention is credited to Jim Maurice Abbey, Christopher Mark Driscoll, David Simpson, Daniel John White, Clive Charles Woolley.
United States Patent |
9,357,111 |
White , et al. |
May 31, 2016 |
Casing
Abstract
Casings and housings for use in high speed airflow (for example
for mounting on a high speed vehicle) are described. In one
embodiment, a housing for imaging equipment is described. The
housing has a tapering form with symmetrical angular truncations
such that it tapers in the form of a wedge with two substantially
planar regions. At least one substantially planar region includes
an aperture formed of optically transparent material.
Inventors: |
White; Daniel John (Salisbury,
GB), Woolley; Clive Charles (Salisbury,
GB), Abbey; Jim Maurice (Salisbury, GB),
Simpson; David (Salisbury, GB), Driscoll; Christopher
Mark (Salisbury, GB) |
Applicant: |
Name |
City |
State |
Country |
Type |
White; Daniel John
Woolley; Clive Charles
Abbey; Jim Maurice
Simpson; David
Driscoll; Christopher Mark |
Salisbury
Salisbury
Salisbury
Salisbury
Salisbury |
N/A
N/A
N/A
N/A
N/A |
GB
GB
GB
GB
GB |
|
|
Assignee: |
QINETIQ LIMITED (Hampshire,
GB)
|
Family
ID: |
44511969 |
Appl.
No.: |
14/129,465 |
Filed: |
June 30, 2012 |
PCT
Filed: |
June 30, 2012 |
PCT No.: |
PCT/GB2012/000563 |
371(c)(1),(2),(4) Date: |
December 26, 2013 |
PCT
Pub. No.: |
WO2013/004991 |
PCT
Pub. Date: |
January 10, 2013 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20140139730 A1 |
May 22, 2014 |
|
Foreign Application Priority Data
|
|
|
|
|
Jul 1, 2011 [GB] |
|
|
1111270.3 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64D
47/08 (20130101); H04N 5/2252 (20130101); G03B
15/006 (20130101); G03B 17/02 (20130101) |
Current International
Class: |
B64D
47/08 (20060101); H04N 5/225 (20060101); G03B
17/02 (20060101); G03B 15/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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201376671 |
|
Jan 2010 |
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CN |
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2 311 433 |
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Sep 1974 |
|
DE |
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2 863 584 |
|
Jun 2005 |
|
FR |
|
A-2006-221366 |
|
Aug 2006 |
|
JP |
|
WO 97/13169 |
|
Apr 1997 |
|
WO |
|
WO 01/77627 |
|
Oct 2001 |
|
WO |
|
WO 03/097453 |
|
Nov 2003 |
|
WO |
|
WO 2010/125994 |
|
Nov 2010 |
|
WO |
|
WO 2011/066410 |
|
Jun 2011 |
|
WO |
|
Other References
International Search Report issued in International Patent
Application No. PCT/GB2012/000563 dated Oct. 30, 2013. cited by
applicant .
Written Opinion of the International Searching Authority issued in
International Patent Application No. PCT/GB2012/000563 dated Oct.
30, 2013. cited by applicant .
British Search Report issued in British Patent Application No.
1111270.3 dated Oct. 19, 2011. cited by applicant .
Corrected British Search Report issued in British Patent
Application No. 1111270.3 dated Apr. 21, 2012. cited by applicant
.
British Search Report issued in British Patent Application No.
1111270.3 dated Apr. 28, 2012. cited by applicant.
|
Primary Examiner: Dinh; Tien
Assistant Examiner: Green; Richard R
Attorney, Agent or Firm: Oliff PLC
Claims
The invention claimed is:
1. A modular casing for sensing apparatus configured to be
externally mounted on a high speed aircraft, the modular casing
comprising: a nose section, at least one body section and one tail
section, wherein said sections are detachably connected to one
another so as to permit disassembly of the casing, and wherein the
nose section has a tapering form with symmetrical angular
truncations such that the nose section tapers in the form of a
wedge with two substantially planar regions and terminates with a
leading edge strip; and mounting means configured to allow the
modular casing to be externally mounted onto the high speed
aircraft, wherein the mounting means comprises a load carrying
structure for providing hardpoint attachments to a host
aircraft.
2. A modular casing according to claim 1 which is roughly
cylindrical in shape along at least a portion of its length.
3. A modular casing according to claim 1 in which the casing
sections are connected by connectors arranged to interact with two
adjacent casing sections.
4. A modular casing according to claim 1 in which at least one
casing section comprises a cut-out portion arranged to provide
access to the interior of the casing and/or to receive an interface
that is configured to allow information gathered by a sensor housed
in the casing to be accessed.
5. A modular casing according to claim 1 which comprises pressure
relief valves.
6. A modular casing according to claim 1 in which the sections are
independently rotatable about the common axis of the casing.
7. A modular casing according to claim 1 which is configured to
house one or more of each of the following: sensor, location
sensor, communication device, driver equipment, memory, battery,
electronic control unit, desiccator, electronic interface.
8. A modular casing according to claim 1, the casing comprising a
housing for imaging equipment, wherein the housing is configured to
be used in high speed airflow, wherein at least one substantially
planar region comprises an aperture formed of optically transparent
material.
9. A modular casing according to claim 8 in which the housing
comprises an ogive form having symmetrical angular truncations.
10. A modular casing according to claim 8 in which both planar
regions are provided by optically transparent materials.
11. A modular casing according to claim 8 in which the strip is
capable of heat conduction.
12. A modular casing according to claim 8 in which the optically
transparent material comprises glass.
13. A modular casing according to claim 8 which further comprises a
base region which is substantially cylindrical in shape.
14. A modular casing according to claim 8 in which the internal
angle of the wedge is approximately 40-45.degree..
15. A modular casing according to claim 8 wherein the housing is
configured to act as a nose cone when the casing is mounted on a
high speed aircraft.
16. A modular casing according to claim 1, the casing being
configured to be mounted on the exterior of an aircraft, the casing
being configured such that at least one of the following
qualities/quantities thereof is similar to that of a known aircraft
store carried by the aircraft to which the casing is intended to be
mounted: length, weight, center of mass, center of gravity, inertia
length, cross sectional area.
17. A modular casing for sensing apparatus configured to be mounted
on a high speed vehicle, the modular casing comprising: a nose
section, at least one body section and one tail section, wherein
said sections are detachably connected to one another so as to
permit disassembly of the casing; mounting means configured to
allow the modular casing to be mounted onto the high speed vehicle
wherein the mounting means comprises a load carrying structure for
providing hardpoint attachments to a host vehicle; and a housing
for imaging equipment, wherein the housing is configured to be used
in high speed airflow, the housing having a tapering form with
symmetrical angular truncations such that it tapers in the form of
a wedge with two substantially planar regions, wherein at least one
substantially planar region comprises an aperture formed of
optically transparent material, and wherein the housing comprises
an ogive form having symmetrical angular truncations.
18. A modular casing for sensing apparatus configured to be mounted
on a high speed vehicle, the modular casing comprising: a nose
section, at least one body section and one tail section, wherein
said sections are detachably connected to one another so as to
permit disassembly of the casing; mounting means configured to
allow the modular casing to be mounted onto the high speed vehicle
wherein the mounting means comprises a load carrying structure for
providing hardpoint attachments to a host vehicle; and a housing
for imaging equipment, wherein the housing is configured to be used
in high speed airflow, the housing having a tapering form with
symmetrical angular truncations such that it tapers in the form of
a wedge with two substantially planar regions, wherein at least one
substantially planar region comprises an aperture formed of
optically transparent material, and wherein both planar regions are
provided by optically transparent materials.
Description
The present invention relates to apparatus and methods for casings,
in particular but not exclusively for casings for sensing apparatus
intended to operate in high stress environments. Associated
apparatus and methods of operation are also disclosed.
There are many occasions where versatile and/or robust sensing
capability is required. One particular example is where imaging (or
other) apparatus may be required to operate in harsh conditions,
for example be subjected to high accelerations, pressures and/or
high speed airflows within its operating environment.
It may be the case that sensing equipment is required on high speed
vehicles. For example, airborne cameras have been used for many
years to record the carriage, release trajectory, near field
effects and characteristics of objects (e.g. packages, missiles
etc, commonly known in the field as `stores`) released from
military aircraft. This imagery is used for many purposes, for
example to verify theoretical modelling predictions of stores
release and the correct operation of arming and safety lanyards,
umbilicals and ejection equipment, flare release, etc. The imagery
is also used to observe at close hand any potentially damaging
conflicts of the released stores with the aircraft and other stores
suspended from it, which in the past has resulted in disastrous
consequences.
Such aircraft can be very fast moving (for example supersonic jets)
or subject to irregular movements (such as high levels of vibration
in helicopters), making for challenging imaging environments. In
order to gather such images, the skilled person usually makes a
choice between mounting a camera on an aircraft carrying the stores
for release, or carrying imaging equipment in a second `chase`
aircraft following closely.
Both methods have associated disadvantages: the use of a chase
aircraft is costly and has also lead to mishaps when the stores
have collided with the chase aircraft. Generally, such cameras are
carried in so-called `pods`, which have typically been based on an
existing aircraft pod manufactured for another purpose with
modifications to enable the fitting of cameras, viewing windows,
adjustment structure and the necessary heaters etc. These pods are
generally aircraft specific i.e. can not be used on other aircraft,
and contain many compromises inherent from their original design
function.
Most such camera pods relied on host aircraft power supplies and
camera triggering function by the aircrew, leading to increased
pilot workload, indeed this has lead in some cases to wasted
`sorties` due to triggering errors caused by high pilot workload
during the critical stores release phase. Further, mounting a
camera on an aircraft can affect its flight characteristics.
Although high speed `wet film` devices, which are bulky and require
a large pod `envelope` to contain them, with high maintenance
requirements and heating facilities, have generally been used, the
film for such cameras is now in short supply as most imaging
equipment is now digital. As these cameras run at up to 500 ffps,
there is a considerable quantity of film stock required for a
typical sortie especially as the cameras require a `run up` period
prior to the trigger event, and are prone to film breakage. Post
processing of the film is costly, and requires the removal of the
film cassettes from the pod and specialist facilities for film
development along with the hazardous chemicals used during
development.
Although the description above has centred on the challenges faced
in aircraft mounted imaging equipment, it will be readily apparent
that technology which solves these problems is also of use in other
fields, and could be of use in land or sea related imaging or
indeed in other forms of sensing (e.g. Radar, LIDAR, or other
sensors devices). Sensors are also used in a fixed positions which
are or may be affected by harsh conditions such as high vibration,
temperature gradients, pressure or supersonic airflow or turbulent
winds or other fluid flow.
The invention seeks to provide an improved method and apparatus for
carrying sensor equipment in high stress environments. In some
aspects, the invention seeks to provide an improved method and
apparatus for carrying sensor equipment (which may in particular be
imaging equipment) on aircraft.
According to a first aspect of the present invention there is
provided a modular casing for sensing apparatus arranged to be
mounted on a high speed vehicle, the casing comprising at least one
nose section, at least one body section and at least one tail
section, wherein said sections are detachably connected to one
another so as to permit disassembly of the casing.
Such a casing may provide a `pod` as described above. Providing a
modular construction which permits disassembly is advantageous as
it allows access to sensor equipment contained within the casing.
Further, a modular casing is adaptable for purpose: it allows
sections to be exchanged or replaced, and allows additional
sections to be added. Prior art camera casings usually comprise a
single body structure, as the manufacturers consider such casings
as relatively cheap, stand alone, and often single use, items.
However, a modular casing is advantageous in that it may be
modified and deployed on many vehicle (e.g. aircraft) types despite
not being originally designed with that role in mind.
In preferred embodiments, the casing further comprises mounting
means arranged to allow the casing to be mounted onto a high speed
vehicle. In particular, the mounting means may comprise a mounting
rail or the like which conforms to existing attachment standards.
This may mean that the vehicle itself need not be modified to
accept the casing.
The casing may comprise a load carrying structure which is arranged
to provide hardpoint attachments to a host vehicle. As will be
appreciated by the skilled person, the term `hardpoint` is a term
of art which refers to part of an airframe (or, by extension of the
term's original use, other non-air vehicles) designed to carry an
external load, and is most commonly used to refer to a hardpoint on
the structure of military aircraft where external stores can be
mounted. The hardpoint attachments are preferably of sufficient
strength to withstand all intended operating conditions, or can be
used with vehicles which operate within the load capabilities (i.e.
speed/gravitational loads/altitude) of the casing. Such a load
carrying structure, or `hardback` as it is known in the art, may
comprise an integral part of at least one casing section.
Providing a load carrying structure adds to the strength of the
casing such that it can be used in a wide range of operating
environments.
In one embodiment, the casing may be roughly cylindrical in shape
along at least a portion of its length. In particular, the casing
may be cylindrical in the region of the connections between the
sections. Providing a casing which is cylindrical along at least a
portion of its length is advantageous in at least the following
ways. First, it provides good aerodynamic performance, further it
encloses a relatively high volume of space for a given amount of
external material and is simple to manufacture. Furthermore, if the
casing is cylindrical in the region of the connections between the
sections thereof, it may allow one section to be mounted to an
adjacent section at any of a range of angles from 0-360.degree.. In
preferred embodiments, each casing section may be independently
mounted at any angle relative to any other section. Of course,
other shapes are possible and allow some freedom in relative
rotation (e.g. four positions for square cross section, six for
hexagonal and so on).
In one embodiment, the casing sections are joined by connectors
arranged to interact with two adjacent casing sections. In one
embodiment, the casing is cylindrical for at least a portion of its
length and the connectors comprise split rings arranged to overlie
and interact (or interlock) with portions of adjacent casing
sections. Such connector rings also allow the relative rotation of
sections (and the independence of rotation of sections), which
enhances modular interchangeability and the adaptability of the
casing configuration. The casing sections may comprise structural
support ribs, e.g. rings, arranged to interact with the connectors.
This provides a simple form of connection. The structural support
ribs additionally provide support for the structure of the casing.
Alternative connectors may include radial through bolts, (which may
be pitched (preferably equally) around the circumference of the
casing), over-centre type latch fixings (which again may be pitched
(preferably equally) around the circumference of the casing and/or
run parallel to the longitudinal axis of the casing), or the
like.
In one embodiment, at least one casing section is arranged to
receive an interface, for example in a cut-out portion thereof,
wherein the interface allows information gathered by one or more
sensor(s) housed in the casing to be accessed.
At least one casing section may comprise an access port arranged to
allow access to the interior of the casing, preferably even when
the casing is assembled and mounted on a vehicle. This allows the
manipulation of and interaction with sensors within the casing.
At least one casing section may comprise an optical aperture,
arranged to allow imaging equipment housed therein to capture
images of the casing's surroundings.
The casing may further comprise pressure relief valves. Such relief
valves may be arranged to allow the pressure inside the casing to
be similar to the pressure outside, for example to within .+-.1
pound per square inch (psi). In such embodiments, at least one high
pressure relief valve and one low pressure relief valve may be
provided.
In a preferred embodiment, the casing, or at least one section
thereof, may comprise an extruded and machined light alloy tube
extrusion. Such a material is relatively light weight for its
strength. For example, at least a section of the casing may be made
of a tube of standard 6061-T6 aluminium alloy, which may be
machined to reduce its thickness. Of course, other alloys, metals,
and indeed other non-metal materials such as fibreglass or other
composite materials may be used by the skilled person bearing in
mind the intended operating environment. In one embodiment, at
least one section may comprise a composite material (e.g.
glass/epoxy). Such a material allows the formation of relatively
complicated and/or detailed shapes but is still capable of
withstanding a reasonable amount of applied force. Further, such a
material is less disruptive to certain signals, such as GPS
signals, when compared to a metal casing.
The casing may be arranged to house one or more of any of the
following: a sensor (e.g. camera, radar transmitter/receiver, LIDAR
transmitter/receiver, location sensor (such as a GPS device), any
other sensor) a communication device, e.g. datalink for allowing
the sensor to be read and/or controlled remotely, driver equipment
for the sensor, a memory, a battery, an electronic control unit, a
desiccator, an electronic interface, or the like
In one embodiment, the casing has a length, weight, centre of
gravity and/or centre of mass similar to that of standard apparatus
carried by the platform/vehicle on which it is intended to be
mounted. This is advantageous as it allows the casing to behave in
a manner which is known from said standard apparatus when it is
carried by the platform. In particular, where the platform is an
aircraft, it allows existing flight data to be used to model
expected behaviour of an aircraft carrying one or more casing
according to the invention.
In some embodiments, the casing may include more than one of a
given casing section. The casing sections may be connected
symmetrically, i.e. any given casing sections may face in either
direction of travel.
In some embodiments, the casing may comprise a bulkhead and/or
baffle arranged between the nose section and the body section(s).
This bulkhead and baffle may be provided as a single entity. This
provides protection for any equipment in the remainder of the
casing in the event that, in use of the casing, any part of the
nose section fails.
Preferably, the casing is cleared for flight in both directions,
i.e. may be flown with the nose section foremost. This adds to the
versatility of the casing.
In one embodiment, the casing comprises a nosecone section, a first
sensor section, a centre section, a second sensor section and a
tail cone section. The first and second sensor sections may be
similar or substantially identical. The centre section may be
attached, for example permanently attached, to a hardback. The
centre section may comprise a control electronics section and be
arranged to house electronic equipment. At least one of the first
and second sensor sections, the nose cone section and the tail cone
section may be arranged to house one or more sensors, for example
imaging equipment. In embodiments housing imaging equipment, the
sections may comprise optical apertures.
According to a second aspect of the invention, there is provided a
casing arranged to be mounted on an aircraft which is cleared for
flight in both a first and a second direction. The casing may be a
longitudinal casing having a first and second end which is cleared
for flight with either the first or the second end foremost. The
casing may have ends which are similar in form (i.e. have
substantially indistinguishable nose and tailportion) or may have
ends which are different but both suitable to act as either a nose
or a tail portion. The casing may be a casing according to the
first aspect of the invention, and/or may be a `pod` for an
aircraft.
According to a third aspect of the invention, there is provided a
housing for imaging equipment, wherein the housing is arranged to
be used in high speed airflow, and the housing a tapering form
having symmetrical angular truncations such that it tapers in the
form of a wedge formed by two substantially planar regions, wherein
at least one substantially planar region is provided by an aperture
comprising a plate of optically transparent material.
The `wedge` shape provides a good level of aerodynamic performance.
Although a dome of some form (e.g. spherical, elliptical, ovate,
ogive etc.) as is known for nosecone design could be used if
aerodynamic performance only was to be considered, and would have
some advantages in that it provides an option for 1-piece
construction and full rotational symmetry (and therefore even
loading), such domes can produce self-imaging or `narcissus`
effects, where a camera captures its own reflection. By using a
plate rather than a curved optically transparent window, this is
avoided.
The underlying (un-truncated) shape of the housing may have any
form, in particular a symmetrical tapering form e.g. conical,
ogive, parabolic, semicircular, etc, as may be familiar from
nosecone design. In one example, the housing comprises an ogive
with a symmetrical angular truncations. Further, the housing may be
a relatively slender ogive as such a shape has improved aerodynamic
properties compared to other ogives with symmetrical angular
truncations.
In some embodiments, both planar regions may be provided by
optically transparent materials. Providing such a `wedge` allows an
optical window on both sides, allowing an almost complete
hemispherical potential field of view for imaging equipment, or
other sensing equipment, mounted in the housing.
The housing may be formed as a nose section of the casing according
to the first aspect of the invention.
The body of the housing may comprise a composite material. As will
be familiar to the skilled person, such a material is relatively
strong for it weight. The housing may further comprise a leading
edge strip, which may be arranged to provide additional support at
the junction between the optically transparent material and the
rest of the housing, and, in embodiments where more than one
optically transparent plate is used, between the optically
transparent plates where they come together at the thin end of the
wedge. It will be appreciated that the term `leading edge` would be
understood by the skilled person to be the edge which moves through
the air (or towards which the air moves), cutting through or
parting the airflow, i.e. the wedge is arranged to taper towards a
leading edge of the housing.
This is advantageous as there can be manufacturing difficulties in
forming a robust joint between optical plates (e.g. glass) which is
capable of surviving longer term effects of use in a high airflow
environment (e.g. the effects of heat, pressure and abrasion). This
leading edge strip may comprise a tough, corrosion resistant
material, such as corrosion resistant steel. The support provided
may be support in view of the additional pressure experienced by
the leading edge of the wedge as it moves though the air, or the
high temperatures experienced by the leading edge of the wedge, or
both in particular at high speeds. To assist in dissipating heat,
in some embodiments, the leading edge strip may comprise a heat
conducting material (corrosion resistant steel also has appropriate
heat conducting properties although other materials will be
familiar to the skilled person). In addition, providing a strip of
material at the very front of the leading edge may be advantageous
as it may deflect abrasive material which would otherwise impact
(and possible scratch) the optically transparent plate(s).
The optically transparent plate(s) may comprise glass, for example
toughened glass. The optically transparent plate(s) may comprise a
coating, such as an optical coating (e.g. antireflective coating or
a filter) or a self-cleaning coating. Preferable, the plate(s) are
optically flat. Such features allow for high quality imaging and
the use of self cleaning/hydrophilic glass, (in which a `treatment`
may be added into the outer layer of the glass as part of the
manufacturing process). In one such example, a titanium dioxide
coating is integrated with the outer glass layer. Use of such glass
reduces or removes the need for protection shutters as are used in
prior art devices while images are not actually being acquired as
contamination accretion is minimized.
Where two plates are used, the plates are preferable similar, more
preferably substantially identical. In any case, the housing is
preferably symmetrical. Both such features both contribute to
ensuring that symmetrical forces are experienced by the housing and
allow for a balanced aerodynamic performance.
The housing may further comprise a base region which is
substantially cylindrical in shape. Such a base region provides an
area in which the imaging equipment and/or additional sensing
equipment may be housed.
In preferred embodiments, the wedge has an internal angle of
approximately 40-45.degree.. Such a wedge angle provides a suitable
compromise between aerodynamic and imaging considerations. A very
acute angle would result in a relatively long optically transparent
plate and, in turn, housing length, which has advantage in terms of
aerodynamics, but a flat plate perpendicular to a camera lens axis
is ideal for imaging (although not totally necessary provided
`narcissus` effects are avoided). In particular, a sharp angle
provides for good imaging (the leading edge of corrosion resistant
steel is barely visible by camera) but the nosecone should also be
kept short in order to keep mass and volume down: an unnecessarily
long structure would waste space. Of course, in environments where
different challenges are faced, there could be an alternative
preferred angle for the wedge and indeed, the housing may have a
different preferred shape depending on the sensor housed
therein.
Limits are placed on the internal angle of the wedge by the
intended speed of operation. For example, a completely square nose
cone is feasible if only low speed air flow is to be encountered.
By contrast, 40-45.degree. is a suitable value for the speed of
military vehicles such as the Tornado aircraft. If high subsonic or
supersonic flight is to be contemplated, the internal angle should
be as small as possible, perhaps 10.degree.-30.degree.. Therefore,
the internal angle might typically fall in the range 30-50.degree.
for the imaging applications described in the specific description,
but could also fall outside this range.
According to a fourth aspect of the invention, there is provided a
casing for sensor equipment arranged to be mounted on the exterior
of an aircraft, the casing being arranged such that, in use, it
exhibits similar characteristics in flight to known aircraft
stores.
This allows the casing to be treated by the aircraft/flight crew in
a similar, if not identical, way to the way in which the known
store is treated, simplifying clearance of the casing for flight,
determining flight plans, fuel usage, the effect of the casing on
aircraft handling, and the like. As will be familiar to the skilled
person, for computer controlled flight systems (e.g. military
aircraft and particularly fighter jets), factors such as a store's
mass, centre of gravity, inertia, positions, etc are used by the
aircraft flight control computer to determine the optimum flight
control limits of the aircraft. A casing which acts as a
`surrogate` version of the known store allows the aircraft to fly
in a way that is already well understood from analysis of such
aircrafts carrying the emulated store, and, by closely emulating
such aspects of a known store can be carried without any associated
flight restrictions or limitations being applied to the host
aircraft and/or removes the requirement for costly reprogramming of
flight computers to enable carriage of the casing.
The casing may be casing according to the first or second aspect of
the invention.
In order to exhibit similar flight characteristics, the casing may
be arranged such that at least one of the following
qualities/quantities is similar to that of a known store: weight,
centre of gravity, inertia centre of mass, length, and the like.
Where applicable, the qualities/quantities should be within about
5-10% with those of a known store. The cross sectional area is
advantageously also similar but in many practical examples, such
casings would not enclose a sufficient internal volume to house the
necessary equipment. The effect of this difference on flight
characteristics can be relatively easily modelled and incorporated
into existing flight plans.
Examples of known stores which could be emulated by the casing are
AIM9/L Sidewinder or ASRAAM missiles, or the like. As will be
appreciated by the skilled person, the Sidewinder and ASRAAM
missiles are two stores in a family (as defined by their
weight/size) of weapons that are the most widely used by military
aircraft. Their physical characteristics are widely publicly
available (see for example, reference sources provided by IHS
Jane's, amongst many other sources) and accord with published
standards. Therefore, emulating their characteristics is
particularly useful.
According to a fifth aspect of the invention, there is provided a
casing according to the first, second or fourth aspect of the
invention in combination with equipment comprising at least one of
the following: sensor (e.g. camera, radar transmitter/receiver,
LIDAR transmitter/receiver, location sensor (such as a GPS device),
any other sensor) communication device, e.g. for allowing the
sensor to be read and/or controlled remotely, driver equipment for
the sensor, memory, battery, electronic control unit, desiccator,
electronic interface, or the like.
According to a sixth aspect of the invention, there is provided a
method of imaging a store release from an aircraft comprising
mounting a casing according to the first, second or fourth aspect
of the invention on an aircraft, the casing housing at least one
camera, a triggering mechanism and a battery, the method comprising
automatically triggering the camera to record the store
release.
The triggering mechanism may comprise at least one of the
following: a break-wire mechanism, a pressure gauge, a heat sensor,
an imaging device arranged to detect a change in the visual image,
a photovoltaic cell or the like.
The memory may be arranged to store video images captured by the
camera and to partition portions of the memory relating to a
predetermined time before and after the triggering mechanism
operates.
According to a seventh aspect of the invention, there is provided a
baffle comprising two opposed faces, the faces containing there
between a series of channels and comprising a plurality of holes on
each face, wherein each hole is arranged to allow air ingress to
and or exit from a channel, the arrangement being such that air
entering a channel via a hole on one face must pass to a different
channel to exit the baffle via a hole formed in the opposed
face.
Such a baffle will slow air incident thereon, limiting the force of
the airflow downstream of the baffle.
In one embodiment, the channels associated with the holes in the
first face are at an angle, for example perpendicular, to the
channels associated with holes formed in the second face. This
causes a change in direction of the airflow, and will therefore
slow it down.
In one embodiment, the faces are formed of two separate plate
elements. The channels may be formed as indentations in the plate
elements, and may provide ribs on the faces. The plate elements may
be secured together to provide the baffle. (The design ensures the
stiffness and strength required in the event of an extreme
overpressure situation) This provides for easy manufacture.
The channels may be linear. This again results in easy manufacture.
Alternatively, the channels may themselves contain corners and/or
curves to further slow the airflow.
In one embodiment, the baffle is arranged to act as a bulkhead
within a casing according to the first, second and/or fourth
aspects of the invention described above. This bulkhead may be
placed between the nose section and the remaining sections.
The preferred features may be combined as appropriate, as would be
apparent to a skilled person, and may be combined with any of the
aspects of the invention.
In order to show how the invention may be carried into effect,
embodiments of the invention are now described below by way of
example only and with reference to the accompanying figures in
which:
FIG. 1 shows an assembled casing for housing sensor equipment and
arranged to be attached to a platform such as an aircraft;
FIG. 2a-c shows a nosecone section of the casing of FIG. 1;
FIG. 3 shows a section of the casing of FIG. 1 arranged to house
sensor equipment;
FIG. 4 shows a section of the casing of FIG. 1 arranged to house
electronic equipment and interfaces;
FIG. 5 shows a tail cone section of the casing of FIG. 1;
FIGS. 6a-c show a connector arrangement for connecting sections of
the casing of FIG. 1;
FIGS. 7a-c show a hardback and an adaptor rail, arranged to allow
the casing of FIG. 1 to be mounted on a platform such as an
aircraft;
FIGS. 8a and 8b show cameras mounted on mountings arranged to be
carried within the casing of FIG. 1;
FIG. 9 shows a cross section of the casing of FIG. 1 including
equipment mounted therein;
FIG. 10 shows a triggering system;
FIG. 11 shows detail of a camera mounted in a nose cone section
according to one embodiment of the invention;
FIG. 12 shows front and back faces of a bulkhead; and
FIG. 13 shows a top view of an assembled casing.
FIG. 1 shows an assembled casing 100 according to one embodiment of
the invention. As explained in greater detail below, this casing
100 is arranged to be mounted on a high speed vehicle (for example
an aircraft which can travel at up to Mach 1.6) and provide
protection for apparatus carried therein in challenging
environments. In this example now described, the casing 100 is
intended to travel at altitudes of up to of 40000 ft. However, the
casing 100 is also suitable for mounting on other vehicles, for
example helicopters, large transport and U.A.Vs where the
environmental challenge may be more associated with vibration and
acceleration than with speed.
The casing 100 comprises 5 sections: a nosecone section 102; three
body sections comprising a first sensor section 104, a control
electronics section 106, a second sensor section 108; and a tail
cone section 110. The sections are linked with connectors 112. The
casing 100 further comprises a hardback 114. Each of these
components is described in greater detail below.
The body sections 104, 106, 108 and tail cone section 110 of the
casing 100 are substantially made of extruded and machined light
alloy tube extrusion, supported by structural elements. In this
embodiment, the connectors 112 interact with support rings made of
corrosion resistant steel which provide structural elements, as
described further in relation to FIG. 9 below. Additional support
is provided by the hardback 114, which is fixed to the control
electronics section 106, and further internal support ribs, which
are described in greater detail below. The use of light alloy
machinings allows the casing to be relatively lightweight
(approximately 88 kilograms when including the interface assembly
described herein after), while still providing a robust structure
capable of operating in a high speed, high force (for example
gravitational forces) and high vibration environment.
The casing 100 is arranged to house up to four cameras (although in
the described embodiment, only three are shown--and additional
camera could be housed by replacing the illustrated tail cone
section 110 with another nosecone 102 to produce a `double ended`
casing 100 (the second nose cone therefore acting as a tail cone).
The structure is relatively compact by design.
The shape of the casing 100 is such that the tail cone section 110
can be placed at the lead end of the casing 100 without adversely
affecting behaviour in flight, i.e. the casing may be cleared for
flight in either direction.
The modular, section-based structure makes the casing 100
adaptable, enabling future modification, and expansion to new
roles, in particular other sensing or monitoring roles. It also
allows for cost effective manufacture, maintenance and operation.
The casing 100 may be expected to have a long--for example 20
year--life expectancy. The casing 100 is further arranged to allow
for simplified servicing, data download from sensors housed
therein, and minimum turn round time compared to existing sensor
casings.
The hardback 114 provides strength to the casing 100 and (in some
examples in conjunction with an adaptor rail as detailed below)
allows for multi platform compatibility, but in order to make
practical use of this, the casing 100 should be capable of
performing its protective function on all such platforms,
preferably without disrupting the platforms themselves. In the
terms of the art, a large `operating envelope` is desired to take
advantage of the adaptability.
FIGS. 2a-c shows detail of the nosecone section 102, which provides
a housing for imaging equipment. As can be seen from the Figures,
the nosecone section comprises a `wedge` shaped section 101 with a
substantially cylindrical base region 103 which may be mounted
within casing 100 at any angle, i.e. may be rotated at any position
through 360.degree. around the longitudinal axis of the casing 100
relative to the position shown in FIG. 1. The `wedge` is formed of
two optically transparent plates, in this example glass panels 202
mounted to a machined aluminium frame 204 which is fixed to a body
formed as a composite shell 206 which is manufactured from a
glass/epoxy composite.
As can be seen from the illustration of the shell 206 in isolation
in FIG. 2C, and the detail of the end of the nosecone section 102
(with the glass panel removed to show the interior detail) in FIG.
2B, the shell 206 comprises an internal bezel 210 arranged to
retail a glass panel 202.
The nosecone section 102 as a whole is broadly a slender ogive
shape with flattened sides (or symmetrical angular truncations) as
it narrows, resulting in a leading edge. The leading edge of the
nosecone section 102 is formed of a corrosion resistant steel
leading edge strip 212 which is bonded in to complementary cut-outs
in the shell 206 (see FIG. 2B in particular). This leading edge
strip 212 cuts through the air, taking the brunt of any impact from
abrasive material (and therefore serves to provide some protection
to the glass panels 202). It also assists in heat dissipation (as
will be appreciated by the skilled person, the leading edge or tip
of a nose cone may get hot as it moves through the air at high
speed). The configuration described also means that the glass
panels 202 are not directly bonded to one another: obtaining a
glass/glass bond of sufficient strength is a technical challenge
which is avoided by use of the intervening strip.
The glass panels 202 provide `aperture flats`, and are manufactured
from high strength glass and are optically flat. The panels 202 are
manufactured to be very similar, preferably identical, to reduce
adverse asymmetric aerodynamic loadings to the casing 100 and its
platform (i.e. the vehicle on which it is mounted).
As will be appreciated, it may be the case that imaging is only
required through one of the panels 202, in which case, the other
panel may be shielded or replaced with an opaque panel to minimise
the radiation received, and therefore potential unwanted
reflections, glare and the like. Alternatively, the shell 206 may
be arranged to receive a single panel, the other planar portion
being provided by the material of the shell 206.
The interior of the nose cone section 102 (and indeed any section
housing imaging equipment) may be painted matte black to minimise
such reflections.
The `wedge` of optically flat glass provides a camera mounted in
the nosecone section 102 a near hemispherical field of view with
virtually no obscuration. Although the frame 204 and/or leading
edge strip 212 may appear in some images, in the present example,
such obscuration will likely be of little relevance as, in this
example, the camera is intended to capture a dropping store which
will not be directly ahead and such obstructions will be of little
relevance as they will be on the periphery of the target image. In
addition, a parallax effect when looking directly forward through
similarly angled transparencies has been shown to cause the leading
edge to disappear from images.
The internal angle for the nosecone `wedge` is, in this example,
45.degree. and is selected as a suitable compromise based on the
conflicting requirements for wide forward camera field of view,
transparency size, reduction of `narcissus effect` caused by
internal reflections, supersonic operation loads with airflow
stagnation, kinetic heating and localised airflow disruption
effects. Although a small internal angle is particularly suitable
to counter adverse aerodynamic effects, a flat plate perpendicular
to the camera lens axis is ideal for imaging (although not always
strictly necessary provided that `narcissus` effects are avoided).
In addition, it is generally desirable that nosecone section 102
should not be too long as such a longer nose cone section 102 will
have an associated higher mass and more `unusable` internal
space.
Of course, in environments where different challenges are faced,
there could an alternative preferred internal angle for the wedge.
It will therefore be appreciated that the nosecone section 102
described herein is selected for a particular purpose and in other
embodiments different considerations may apply, for example to
optimize for any particular sensor and/or intended operating
conditions. The nose cone 102 could readily be replaced with a nose
cone of a different design so long as the interconnectivity with
the adjacent section remains consistent. An example method of
connecting the sections is described in greater detail below.
The high strength glass used in the panels 202 has a hydrophilic
self cleaning property which reduces imaging problems associated
with rain and dirt accretion.
The base region 103 of the nosecone section 102 is open and
comprises a structural interface ring 208. Each of the sections
102-110 comprise at least one such ring 208, as described in
greater detail below. The rings 208, which in this embodiment are
made of corrosion resistant steel, are arranged to provide strength
to the structure of the casing 100 when assembled and also to
provide an interface allowing coupling to an adjacent section
102-108 using connectors 112.
Initial aero load Computational Fluid Dynamic models of a nosecone
section 102 design as described herein suggest that, for an
aircraft moving at Mach 1.2 at 1000 ft above ground level there is
a maximum expected localised stagnation temperature of 369K and
pressure of 236 Kp, which the materials and forms used for the
nosecone section 102 are able to withstand.
The nosecone section 102 is arranged to house a high speed digital
camera on an adjustable mount and a GPS antenna used with an Inter
Range Instrumentation Group (IRIG) unit for accurate time stamping
of gathered imagery. As an alternative, a datalink antenna could be
used. These components are described in greater detail below.
The nosecone section 102 is arranged to be connected to a first
sensor section 104. The first 104 and second 108 sensor sections in
this embodiment are substantially the same and their structure is
as shown in FIG. 3.
The sensor sections 104, 108 in this example comprise a cylindrical
body 302 with cut outs, machined from a single machined light alloy
tube extrusion. The body 302 comprises a structural interface ring
208 about each end and has two cut out portions which are opposed
on either side of the length of the cylinder and arrange to
receive, interchangeably, an access panel 304 and a glass panel
306. The sensor sections 104, 108 are attached via the connectors
112 to the adjacent sections. Each of the sensor sections 104, 108
may be mounted at any position, although this is limited in
practical terms to 110.degree. in the present embodiment as the
ends of the hardback 114 protrude over the panel 306: if the
sections 104, 108 were rotated to face the hardback 114, the camera
view would be obscured. The whole section rotation reduces the need
for an internal camera adjustment mechanism in elevation relative
to the pod C/L and also minimizes the vertical aperture size
required (as the skilled person will appreciate, if the overall
cross section of the casing 100 can be kept small, benefits such as
reduced mass, lower aerodynamic load and fewer structural
complications are seen). In this example, and as described in
greater detail below, the cameras are mounted on a base plate
enabling 30.degree. azimuth adjustment.
The access panel 304 is a quick release panel which allows a
sensor, for example a camera or GPS unit, carried in the sensor
section 104, 108 to be readily accessed. In this embodiment, the
fastenings are `Tridair` quick release fastenings manufactured by
Alcoa Inc, but other fastenings will be familiar to the person
skilled in the art.
The glass panel 306 comprises high strength glass which has a
specialized hydrophilic self cleaning property to reduce imaging
problems associated with rain and dirt accretion. In addition, in
some prior art camera casings, in particular camera pods for
aircraft, shutters were provided such that the panels could be
covered when no imaging was being carried out. Although such
shutters may be provided (for example to obscure a panel when not
being used as an aperture), such a coating reduces the need for
shutters and therefore can provide additional benefits in terms of
reduced complexity and weight.
The control electronics section 106 is shown in FIG. 4 comprises an
open cylindrical body 402 machined from a single 4 mm thick
machined light alloy tube extrusion with a number of--in this
embodiment six--substantially rectangular cut out portions. The
control electronics section 106 is terminated at each end of body
402 with structural interface rings 208. Five of the cut out
portions carry quick release access panels 404 mounted therein,
which are arranged to allow easy access to equipment stored
therein, for example enabling easy battery changes. The sixth is
arranged to carry a control and interface panel mounted therein. As
described in greater detail below, such an interface may provide
external power supply connection, digital data download and upload
facility (via laptop interface), system test and monitoring and the
like.
The control electronic section 106 further comprises five ports 406
arranged along the length of the control electronic section 106 and
provided to receive (in this example, permanent) attachments for
the hardback 114 and/or valves as described below. The control
electronic section 106 further two cable access ports 408, one at
each end thereof.
Although not visible in FIG. 4, to ensure that the control
electronic section 106 loadings are distributed to the hardback
114, and there is sufficient stiffness around the access panels, it
further comprises four internal light alloy support rings--these
rings can be seen in FIG. 9.
These rings also form mounting structure for internal equipments.
The control electronic section 106 in this embodiment is arranged
to carry quick change lithium Ion batteries, IRIG time-code
generator and an Event Trigger Control unit.
An exploded view of the tail cone section 110 is shown in FIG. 5.
The light alloy tail cone section 110 is an `aerodynamic fairing`,
comprising a substantially frustro-conical body 502 with curved
side walls and a quickly detachable cap 504, which completes the
rounded conical shape, i.e. an `ogive`. The cap 504 also acts to
secure a desiccator 506, which is housed within the body 502 of the
tail cone section 110. The desiccator 506 in this embodiment is a
removable molecular sieve desiccator and incorporates a status
indicator, in this example having a working capacity of 280
litres.
At the base of the cone shape, the tail cone section 110 comprises
a structural interface ring 208.
This tail cone 110 can be substituted for a nosecone 102 section,
enabling additional rearward imaging if desired. Indeed it will be
appreciated that the tail cone design may be readily adapted
without unduly effecting aerodynamic performance in many
circumstances: an alternative shape, even a squared off end, may be
used in a range of circumstances. The tail section is therefore any
section intended to be mounted at the rear of the casing as it is
moves relative to the air flow.
The sections 102-110 of the casing 100 are fixed together using
connectors 112, which in this example comprise split rings, as
shown in greater detail in FIG. 6a-c. FIG. 6a shows detail of a
cross section of two structural interface rings 208a, b held
together by a split ring connector 112.
In the illustrated embodiment, one of the structural support rings
208a is mounted within the nosecone section 102 and includes a
flange 604 arranged to retain a bulkhead described in greater
detail below. The two rings 208a, 208b are complementary, forming a
physical overlap. The connector 112 ensures that the overlap is
maintained (i.e. that the sections do not slip apart) but it is the
material of the rings 208a, 208b which provide the structural
strength of the joint. In the embodiment described herein, each of
the intermediate sections 104, 106, 108 has a paired set of rings
208 at each end such that each can be rotated about its length.
FIG. 6b shows the two semicircular connector elements 602a, 602b
which may be clamped together using bolts inserted as shown by the
dotted lines in FIG. 6c.
The use of such split rings provides simple assembly and
disassembly, which in turn allows sensors and equipment carried in
the housing to be readily accessed and/adjusted. The system also
allows the sections to be re-arranged, modified, replaced or added
to, which means that the casing 100 is adaptable. It will be noted
that one type of connector 112 is used to connect each section,
simplifying the design. Alternative types of connectors 112 will
however be familiar to the skilled person such as radial through
bolts equally pitched around the circumference of each joint,
over-centre type latch fixings equally pitched around the
circumference and running parallel to the casing 100 axis or the
like.
FIGS. 7a and 7b show respectively perspective views of the top and
the underside of hardback 114, i.e. an integral, stiff load
carrying structure which is arranged to form the primary connection
from casing 100 to a host vehicle. The hardback 114 is arranged to
be attached to the control electronics section 106 and comprises
and elongated lozenge-shaped body made of a one piece machined
aluminium structure, in which a number of ports are formed. In
particular, the hardback 114 comprises three access panels 702
which are covered by detachable plates 703 in the embodiment of
FIG. 7 but in other embodiments may carry interface panels which
are connected to apparatus housed within the control electronics
section 106. Two of these access panels 702 are arranged to align
with the cable access ports 408 of the control electronics section
106 when the casing 100 is assembled, the central access port
overlying the central port 406 of the control electronics section
106. The access panels are sized/positioned such that they are
compliant with known MIL-STD-8591H aircraft interfaces. This
standard is readily available from various sources
The hardback 114 further comprises two.+-.1 psi pressure relief
valves 704 which both operate in an over and under pressure
condition and are arranged such that, when the casing 100 is
assembled, they are in fluid communication with the interior of the
sections of the casing 100, allowing the pressure within the casing
100 to be controlled or to equalise with its environment. The
pressure relief valves 704 are separated by 30 inches and are
arranged to align, when the casing 100 is assembled, with two of
the ports 406 of the control electronics section 106. In this
embodiment, the placing of the valves 704 can be spaced at either
30 inches or 14 inches. As will be familiar to the skilled person,
there are sets of standard `spacings` employed to mount stores to
military aircraft in accordance with an interface as specified by
MIL-STD-8591H: 30 inches and 14 inches, which are used for heavy
and light class stores respectively. Western military aircraft use
this standard to allow the fitment of a very wide range of stores.
By providing the casing with facilities for both within the
hardback 114, the casing can be mounted according to either
standard. Therefore, the pressure relief valve fittings and
mountings for attaching to an aircraft (described in greater detail
below) are interchangeable mounted at either spacing: if a 30 inch
interface is required, then the valves will be separated by 14
inches, and vice versa.
On the upper face thereof, the hardback 114 comprises attachment
lugs 706 which, in the illustrated embodiment are separated by 14
inches (but could be exchanged with the relief valves 704) and are
arranged to allow attachment to an aircraft. Suitable lugs are MACE
fittings or Bale lugs (which are used with sway braces for which
the hardback has been sized and profiled), which accord with
MIL-A-8591H. As will be familiar to the skilled person, MACE is an
attachment fixing method for stores used exclusively by Tornado
aircraft and Bale lugs are a more widely used fixing which use
external sway braces for the store. In this embodiment, as the
hardback 114 provides structural support to the casing 100, the
control electronics section 106 and the hardback 114 are intended
to be permanently attached to one another following manufacture.
The attachment lugs 706 also allow attachment of an adaptor rail
708 shown in FIG. 7C.
The adaptor rail 708 is arranged to provide an interface with a
standard attachment and comprises a machined alloy `ski-shaped`
rail with lug ports 710 for receiving the attachment lugs 706,
cable fairing 712 and steel lug `saddles` 714 which are bolted to
the adaptor rail 708 and arranged to allow attachment to a platform
arranged to carry an LAU-7 missile launcher (For further
information on the LAU-7/A (series) guided missile launcher, refer
to published guide NAVAIR 11-75A-54). As will be familiar to the
skilled person, such attachments exist as standard on many
aircraft, in particular military aircraft, and therefore such an
adaptor rail 708 may be of use if the casing 100 is to be mounted
on such aircraft. A quickly detachable nose part of the rail allows
for cable routing from the casing to the aircraft via the LAU-7
pylon.
FIGS. 8A and B show examples of cameras 802 arranged on mountings
804, 806 which are suitable for mounting in the nosecone 102 and
the sensor sections 104, 108. In this example, the cameras are high
speed cameras. The cameras 802 can be programmed, focused and
adjusted `on wing` in real time by an operator from an external
computer, thus ensuring the fidelity of captured images. The images
are stored on HD cards which may be removed from the camera 102.
One example of a suitable camera is the Phantom Miro 3 manufactured
by Vision Research, Inc.
The cameras 802 therefore are associated with a memory, in this
case each containing 5 MB HD memory card. In use, they are arranged
to be continuously on and run a looped video recording system,
capturing and segmenting only the images required as defined by the
operator settings around the trigger event mark (for example, store
from a minute before and to a minute after a drop). This portion of
memory is segmented but recording continues to loop around the
remaining memory such that multiple drops may be recorded during a
single sortie if required and subject to the remaining memory left
on the camera HD card (5 MB in this example, but this could be
increase if required).
The mountings 804, 806 allow the cameras 802 to be rotated through
a range of positions (i.e. they have Range of Movement, or R.o.M),
in this example through 30.degree., and secured in a position by a
bolt 808 mounted in a cut-out slide arc 810. The mounting 804, 806
and camera are arranged such that the lens `nodal` point is
coincident with the rotation point, which ensures that there are no
odd imaging effects when swinging the camera 802 to view different
target images. It will also be recalled that the sections may be
mounted together at a range of angles, which provides further
freedom in the pointing direction of the camera 802. The mountings
804, 806 are also shaped to follow the contours of the base of the
section in which they are to be housed, allowing them to be
securely fixed therein.
This particular R.O.M was selected considering the maximum
requirements for image field of view in the scenario of monitoring
store release. Given the use of wide angle lenses, any further
rotation of a camera 804 mounted in a nosecone section 102 to the
side is unnecessary as the images gathered by the sensor section
104, 108 mounted cameras 802 would produce an overlap with it, thus
giving the a continual strip image. There are however no practical
limits on this and the cameras 804 could be arranged to rotate by a
full 360.degree. if required.
In addition, the cameras 802 are arranged to be adjustable by 30 mm
relative to the mounting 804, 806 and secured in place by a bolts
812 mounted in a cut out slide lines 814, only one of which can be
seen in FIG. 8 but, as can be seen from FIG. 11 three such bolt/cut
out pairs are provided to add to the stability of the platform.
This allows for different lens types, and/or changes in focal
length to be employed.
Once the cameras 802 are mounted within the casing 100, the access
panels 304 allows camera adjustment, even when the casing is
mounted on the platform including accurate pointing, focus and set
up of the cameras before imaging (e.g. imaging sorties), for
example by use of a laptop or other computing equipment to view
through each camera 802, which may be accessed directly or by
connection via an interface on the control electronics section
108.
FIG. 9 shows a cross section of an assembled casing 100 carrying
exemplary equipment. The casing 100 carries three cameras 802, one
in each sensor section 104, 106 and one in the nosecone section
102. In addition, a GPS antenna 902 is mounted in the nosecone 102
(it will be appreciated that the nosecone is a composite: the other
sections are metal and could disrupt the GPS signal). This GPS
signal is used to time stamp the images taken and alternative
systems (e.g. datalink) could be used which also comprises a
protective bulk head 904 (described in greater detail in relation
to FIG. 12 below) mounted between the nosecone 102 and the first
sensor section 104. Internal support rings 914 are arranged at
intervals along the interior of the control electronics section 106
as described above.
In the control electronics section 106, there is provide a control
and interface panel 906, an event trigger control unit 908, an IRIG
unit 910 and a battery housing 912.
In the example now described, the control and interface panel 906
is arranged to allow information stored on the cameras 802 to be
downloaded. The control and interface panel 906 also comprises a
battery power indicator, trigger alert LEDs (which provide a `press
to test` facility ensures the validity of the trigger system
circuit that is temporarily fitted to the aircraft and the correct
functioning of the cameras), a control interface for the IRIG unit
910, a power input used for ground power during set up, a
master/slave setting facility so that, if there are two casings 100
fitted to an aircraft, one casing 100 can act as the master and one
as the slave (this addresses a problem that may otherwise arise as
both/all of the casings 100 may take timestamp information from
their own GPS unit: only one timestamp can be used otherwise
conflict will arise (even milliseconds discrepancy could produce
errors).
In this embodiment, the battery housing 912 houses two UBBL10
Lithium-Ion batteries (although provision is made for 3 for
additional duration if required) which are arranged to power all of
the electrical components. These batteries have a nominal capacity
of 33V at 6.8 Ah each, weigh a maximum of 1.44 Kg each, are
certified from -32.degree. C. to +60.degree. C., and have a thermal
trip at 70.degree. C.+/-5.degree. C. The batteries' chemistry is
manganese (spinel) which provides superior thermal stability as it
withstands temps up to 250.degree. C. compared to 130.degree. C. of
the cobalt alternative. As can be seen from the table below, the
batteries are capable of powering the electrical components for in
excess of 9 hours. Therefore, these batteries have been selected
given the proposed operating equipment and conditions. Other
equipment/conditions may require different batteries
In particular, in this embodiment, the electrical requirements of
the various components are approximately as follows:
TABLE-US-00001 Miro 3 Camera (.times.3) 1.09 Amps IRIG 0.11 Amps
ETCU (estimated) 0.10 Amps Trigger alert LED (.times.4) 0.06 Amps
GPS Antenna 0.02 Amps Battery Status Indicator 0.03 Amps Estimated
total power consumption 1.41 Amps
Two Li-Ion batteries rated 6.8 Ah @ 33 volts therefore provide
13.60 A/hour, and can therefore power the equipment for
approximately 9 Hrs 38 mins
The assembled casing 100 carrying the equipment described has
sufficient power reserves to run independently for in excess of 9
hours.
In this embodiment, the cameras 802 are provided to record video
images of an event, in particular the release of stores from an
aircraft carrying the casing 100. The trigger mechanism used in
this embodiment comprises, as is shown in FIG. 11, `break wires`
120, i.e. wires which are physically broken by dropping stores
(although in other embodiments, they could be broken by opening
clamps or other physical triggers or indeed by pressure or chemical
changes). This is a simple way of ensuring that a signal occurs at
a relevant time and enables the recording system to be autonomous
(such that, in the event that the casing 100 is to be used on an
aircraft, the aircrew will not have to trigger the camera
separately to releasing the store, easing the burden on the
crew).
In the embodiment illustrated in FIG. 10, the break wires 120 are
attached via sacrificial junctions 122 (e.g. `Jiffy` junctions) to
junction modules 124. The break wires 120 are also attached to the
store release mechanism. When a store is jettisoned, a wire 120
breaks and causes a voltage spike in the system, which is measured
by the event trigger control unit 908 and noted as an event mark.
This mark is time stamped and used as the event signal around which
the cameras 802 are programmed (during set up) to record and
segment images.
As noted above, the cameras 802 each include a memory card. They
are always on and run a looped video recording system, capturing
and segmenting only the images required as defined by the operator
settings around the trigger event mark (for example, store a minute
before and after a drop). This portion of memory is segmented but
recording continues to loop around the remaining memory such that
multiple drops may be recorded during a single sortie if required
and subject to the remaining memory.
There are of course many other methods of triggering the cameras
802 or other sensors carried in the casing--for example, a change
in pressure (such as a aircraft reaching a certain altitude, a
submarine craft reaching a certain depth, or a change in
atmospheric pressure indicative of a notable change in the weather
or environment) could be detected. The sensors could be triggered
by detection or absence of a heat source (as some intruder
detectors and fire alarms), a change in the visual image (as will
be familiar from intruder detectors and other areas), photovoltaic
cells triggered by a flares release (particularly in the imaging of
such flares), or the like.
FIG. 11 shows some further detail of a camera 802 mounted in a
nosecone section 102. As noted above, the shape of the nosecone
section 102 is a compromise between aerodynamic performance,
structural considerations and imaging requirements. FIG. 11 also
shows how a camera 802 mounted in such a nosecone section 102 could
be placed to optimise the imaging conditions. FIG. 11 also
illustrates the shape of the nosecone section 102, i.e. the
substantially conical base portion 206 (a slight curve following
the line of the ogive profile can be seen), and the triangular
cross section of the wedge (i.e. the symmetrical angular
truncations to the narrow ogive form)
It will be noted that the camera 802 pointing direction is offset
from the longitudinal axis of the nosecone section 102 by
10.degree., and can be slewed on its mounting 806 by a further
30.degree.. This means that the imaging out of one of the panels
202 is optimised although, as the entire nosecone section 102 can
be rotated about its axis by 360.degree., the direction that this
panel 202 faces can be set as required for a given operation (e.g.
to observe a store drop vertically down or be released forwards, or
the like). This in turn means a virtually `hemispherical` field of
view can be acquired by adjustment of the nosecone section 102 and
use of wide angle lenses. It should also be recalled that, in this
embodiment, the camera 902 in the nosecone section 102 is working
in conjunction with the cameras 802 in the sensor sections 104, 108
and therefore the chosen range of angles may be complementary to
the field of view of those cameras, e.g. to ensure that a
continuous image can be stitched together from the images produced
by the, in this embodiment, three cameras. The relative angle of
lens to a panel is between 30 and 60.degree., which has the effect
ensuring minimum narcissus effect.
FIG. 12 shows of two faces of the bulkhead 904 which comprises a
`grill` or baffle arranged to disrupt the airflow in the event that
the glass panels 202 or any other element in the nosecone section
102 fails. The design is such that airflow is diffused: although
some air will enter the remaining casing sections, this airflow
will not be powerful enough to damage the components housed
therein.
Specifically, in this embodiment, the bulkhead 904 comprises two
mating faces--a forward face 131, and a back face 133, each of
which is formed with a series of indentations which can be seen on
the external faces as protruding ribs 123, which run in
perpendicular directions on mating faces 131,133. The indentations
of the ribs 123 form perpendicular crossing channels between the
mating faces 131, 134. The bulkhead 904 also comprises holes 125 to
allow air to flow therethrough, half turn locking keys 127 arranged
to cooperate with holes formed in the retaining flange 604 of the
nosecone section interface ring 112, and a handle 129 on the back
face 133. The bulkhead 904 can easily be removed to allow manual
access to a camera or other sensor housed in the nosecone section
102 via an access panel 304 of the sensor section 104, and the
bulkhead 904 can be removed by releasing the locking keys 127 and
removing it with the handle 129.
In the event that the front end of the casing 100 fails, the
airflow passes through the network of holes 125 in the forward face
131, which are aligned with the internal channels provided by the
ribs 123 on the mating back face 133. In order to exit the bulkhead
904, the air is then made to turn at 90.degree. to enter the
channels formed by the ribs 123 on the forward face 131, which are
aligned with the holes on the back face 133. The air passes down
inside the ribs 123 and out again via the holes 123 perforating the
back face. In this way, the air flow is baffled but not completely
restricted.
In this embodiment, the size, mass and inertia of the casing when
loaded with equipment are closely comparable or matched to a known
store. This means that an aircraft carrying the casing 100 can be
controlled and will respond in the same way as is known from flying
the aircraft with the known store. In that sense, the casing 100
may be seen as a `surrogate` version of, or to emulate, the known
store by the flight control systems of aircraft. This removes the
need for an extensive new flight control law programming and
evaluation of the aircraft's native flight control system as would
be required for a `new` store. However, in some cases, the effect
of minor differences may be modelled and used to modify existing
flight control laws.
FIG. 13 shows the loaded casing, when attached to the adaptor rail
708 (which itself has a mass of around 8 Kg) has a mass of
approximately 88 Kg. Length, centre of gravity and inertia is
chosen to be as close as practicable to that of an AIM/9L
Sidewinder missile or an ASRAAM missile, enabling where necessary,
simplified flight clearances on airframes cleared for use of these
stores as a minimum.
As noted above, the Sidewinder in particular is a widely used
store, and its physical specifications are widely publicly
available. Many military aircraft will have established flight
control laws for flying with one or more Sidewinders mounted
thereto.
As can be seen from FIG. 13, the saddles 714 on the adaptor rail
708 are spaced at 30.46'' and 34'', the standard position of the
attachments as defined by published standards. In addition, the
centre of mass (indicated by a dashed line) of the casing 100 is
aligned with the position of the centre of mass of a Sidewinder and
an ASRAAM (which are themselves aligned) when suspended from an
aircraft by the standard attachment means (i.e. is spaced from the
attachments along the length by the same measurement. Indeed, the
centre of gravity and centre of mass is aligned lengthwise within
the specified tolerances within such stores, which is generally
within about .+-.10% but may be kept to within .+-.5%. In addition,
the casing 100 is arranged such that, when loaded and suspended
from the adaptor rail 708, its centre of mass is just 93 mm lower
than that of a Sidewinder missile similarly suspended, which does
not greatly effect flight characteristics while providing
sufficient internal volume for the casing 100 to house the desired
equipment. However, in other embodiments, these may be more closely
aligned.
Depending on the equipment used, ballast may be added to, or
arranged within, the casing 100 to ensure the characteristics match
known stores.
Of course, the sensor/control electronic/nosecone and tail cone
sections described herein could each independently be replaced with
bespoke adaptations. In particular, the casing 100 could, within
practical limits, be converted for use as a flight vehicle
structure for the test and evaluation of a wide number of airborne
sensors. The modular structure approach allows future adaptability
to uses other than the specific example of high speed imaging
described herein.
It will be appreciated that, provided that the interfaces remain
consistent, there is (subject to aerodynamic considerations given
the intended use) no limitation to the profile of any given
section: each section could therefore be replaced with a bespoke
section of any profile.
Although the description above refers to the use of a relatively
light alloy for the majority of the sections, which was selected
based on the criteria of strength/weight, manufacturability and
cost, the material from which any section is dependant on its
intended function. For example, if the casing 100 is to be attached
to an aircraft, any aerospace type composite or metallic
construction would be acceptable subject to stress analysis
clearances. There may however be higher strength requirements for
any section which includes hardpoint attachments in some
embodiments.
Any range or device value given herein may be extended or altered
without losing the effect sought, as will be apparent to the
skilled person for an understanding of the teachings herein.
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